Steam superheater



July 31, 1923.

A. COTTON VSTEAM SUPERHEATER Filed June 6. 1921 INVENTOR ALFRED Cor'rouI g e upca W A'ITORNEY5 Patented July 31, 1923.

UNITED STATES PATENT OFFICE.

ALFRED COTTON, OF ST. LOUIS, MISSOURI, ASSIGNOR TO HEINE BOILER COMPANY.OF ST. LOUIS, MISSOURI, A CORPORATION OF MISSOURI.

STEAM SUPEBHEATEB.

Application filed June 6,

T 0 0H whom it may concern.

Be it known that I. ALFRED Co'rroN, a citizen of the United States,residing at St. Louis, Missouri. have invented a certain new and usefulImprovement in Steam Superheaters, of which the following is a full.clear, and exact description. such as will enable others skilled in theart to which it appertains to make and use the same.

' This invention relates to steam super' heaters.

One object of my invention is to provide a steam superheater that willproduce the amount of superheat desired with a moderate amount ofheating surface and which is so constructed that the degree of superheatcan be accurately controlled.

Another object is to provide a superheater boiler of novel construction.in which the superheater is easily accessible from the outside of theboiler. both for cleaning and for renewal of the superheater elements.

Another object is to provide a water tube boiler having a superheatcrchamber whose Walls are supported in a novel manner that simplifies andreduces the cost of constructing the boiler.

Another object is to provide a front wall construction for water tubeboilers that makes it possible to obtain a relatively large combustionchamber Without the use of complicated arches or a suspended roof forthe furnace of the boiler.

And still another object is to increase the heating surface of a watertube boiler without having a relatively great heat .loss through thefront wall of the boiler. Other objects and desirable features of myinvention will be hereinafter pointed out.

To this end I have devised a superheater that comprises a chamberarranged in com munication with a combustion chamber. a steamsuperheater in the chamber of the superheater. and a means separate anddistinct from the superheater in said chamber for producing a vigorousdraft or current of hot gases over the su erheater. \Vhen my inventionis embodie in a water tube boiler, as herein shown, the superheaterchamber is preferably arranged between the combustion chamber and thefront wall of 1921. serial. No. 475,333.

the boiler in communication with said conibustion chamber. and the meansfor pro ducing a vigorous draft or current of hot gases through saidsuperheater chamber consists of water tubes which cause the gase thatenter the supcrheater chamber to cool rapidly and become of much greaterdensity than the hot gases in the combustion chamher. The Water tubesjust referred to that are arranged in the superheater chamber co operatewith other water tubes arranged in the combustion chamber of the boilerto form an auxiliary Water circulating path that is outside of the mainwater circulating path of the boiler. and said auxiliary water tubes arepreferably used to support the front wall of the boiler and the wall orbattle which separates the superheater chanr her from the combustionchamber. I have herein illustrated my invention embodied in a boiler ofthe type disclosed in my pending application Serial No. 366296. filedMarch 16, 1920. which is provided with four banks of upright watertubes, but I wish it to be understood that my invention is applicable tovarious other types of water tube boilers such as the Stirling. Ladd.Badenhausen and Connelly boilers now in general use.

The figure of the drawings is a vertical longitudinal sectional view ofa water tube boiler constructed in accordance with my invention.

Referring to the drawings, A, B and C designate the elevatedsteamand-watcr drums of an upright. bent tube boiler. D designates theusual mud drum and 1. 2. 3 and 4 designate four banks of upright watertubes that co-operate with said mud drum and steam-and-water drums toform the main water circulatory path of the boiler. The boiler can beprovided with any suitable system of battling for causing the gases tocirculate over the tube banks. but it is preferable to arrange a bailieE at the rear side of the front bank 1 so as to cause the gases to flowupwardly through the combustion chamber F. as indicated by the singleheaded arrows in the drawing.

The oiler comprises a superheatcr chamber G that is equipped with asuperheatcr H, and in the form of my invention herein illustrated saidsuperheater chamber is arranged at the front side of the boiler and isformed by the front all 5 of the boiler setting. and a battle orpartition wall 6 that separates the supcrheater chamber G from thecombustion chamber F. said baflie 6 having gas inlet openings 6* at theupper end of same that establish direct communication between thesuperheater chamberand the combustion chamber. At the lower end of thesuperheater chamber are gas outlets or discharge openings 6" formedpreferably in the lower end portion of the baffle 6. In order to producea vigorous down draft through the superheater chamber G and alsoincrease the heating surface of the boiler, l have provided the boilerwith an auxiliary water circulatory system composed of a bank of watertubes 7 arranged inside of the superhcater chamber. a bank of tubes 8arranged inside of the combustion chamber F and a water drum 9 connectedto the lower ends of the tubes 7 and R and arranged preferably justabove the arch i over the stolter or other tiring apparatus of theboiler. the upper ends of the tubes 7 and 8 being connected with thefront stcam-and-water drum of the boiler when the boiler is of the typeherein shown. It is immaterial. however. so far as my broad idea isconcerned. what particular portion of the boiler the upper ends of thetubes 7 and 9 are connected with, so long as they are tapped onto themain water circulatory system of the boiler in such a way as to insurewater circulating through said tubes when the boiler is in operation.The front wall 5 otthe boiler setting is preferably supported by thebank of tubes 7, and the battle or partition 6 that forms the inner wallof the superheater chamber G is preferably supported by the bank oftubes 8. damper 11 is provided for controlling the exit of the gasesfrom the superheater chamber. and while it is immaterial what particulartype of superheatcr is used, I pre fer to equip the boiler with asuperheater ll which comprises headers 12 arranged on the outside of theboiler setting.

When the boiler is in operation some of the gases that circulateupwardly through the combustion chamber F enter the superheater chamber(i through the opening 6 at the upper end of said chamber. and uponcoming in contact with the water tubes 7 in aid superhcatcr chamber.will cool rapidly and become of much greater density than the hot gasesin the combustion chamber F. siphon or negative chimney effect isthereby produced. which causes a vigorous down draft or current of hotgases through the uperlu-ater chamber. The superheater elements withinsaid chamber are therefore exposed to a rapid How of hot gases whichhave entered the upper end of said chamber from the combustion chamber,and which,

after circulating over the superheater. return to the combustion chamberthrough the exit 6 at the lower end of the superheater chamber. thedamper 11 making it possible to control the return of the cool gases tothe combustion chamber. and thereby regulate the degree of superbeatattained. The two banks of tubes T and 8. together with the water drum9. provide a circulatory path independent of the main water circulatorypath of the boiler but. sharing the front steam-and-water drum with themain water circulatory path. the inner bank of tubes 8 constituting anupcomer bank that is subjected to radiant heat and the outer bank 7constituting a downcomer bank that is subjected mainly to convectedheat.

In view of the fact that the mean temperature of the gases in thesuperheater chamber (i is much less than the temperature of the gases inthe combustion chamber F. much less heat will be lost through the frontwall of the boiler than would be the case if no chamber were interposedbetween the front wall of the boiler setting and the combustion chamber.Moreover, as the gases which lea \c the superheater chamber re-enter themain body of gases in the combustion chamber and pass over the boilerheating surface. said gases are thereby finally reduced to a lowertemperature than the usual ten'iperature of gases leaving a superheater,thus increasing the efficiency of the boiler. Owing to the vigorous downdraft throu h the superheater chamber and among t to down-comer tubes 7in said chamber. the heating surface of these tubes is very effective.and ac cordingly. said tubes form a valuable addition to the heatingsurface of the boiler without increasing the lloor space required forthe boiler. The upcomer tubes 8 of the auxiliary water circulatory pathmay be substantially vertical when floor space is Very valuable. butwhen said tubes are inclined downwardly and forwardly from the frontsteam-andwater drum A of the boiler. as herein shown. a considerableaddition to the volume of the combustion chamber F is obtaint-d and thisimproves the combustion and increases the efficiency of the boiler. Asthe superheater H is not exposed to radiant heat. it will notdeteriorate or burn out rapidly. and as the headers 12 of thesuperhcater are arranged outside of the superheater chamber in anaccessible position at the front of the boiler. the superheater elementsmay be re placed very easily from the outside of the boiler.

I am aware of the fact that a water tube boiler has l'ieretofore beendevised in which a superheater is arranged in a chamber located betweenthe combustion chamber and the front wall of the boiler setting. but insaid prior boiler the flow of the gases through the super-beater chamberis dependent upon the small amount of cooling of the gases by thesuperheater elements. Consequently, as very little cooling of the gasescan be effected by the superheater elements, very little siphon ornegative chimney efi'ect is obtained. In fact, the as circulationthrough a superheater chamber that is e nipped merely with a superheateris very s uggish as compared with the vi rous circulation through thesuperheater c amber of my improved boiler, caused by the bank of watertubes 7 in said superheater chamber. In the prior boiler just referredto the wall between the combustion chamber and the superheater chamberis of the self-support- .ing type, and as it is exposed to hot gases onboth sides, it deteriorates rapidly; In my boiler the wall or battle 6that separates the combustion chamber from the superheater chamber issupported throughout its entire area by a bank of water tubes 8, andaccordingly, it is very substantial and rigid.

This, coupled with the fact that my boiler has an extra tube bank whichdoes not increase the floor space required for the boiler and isprovided with a. relatively large combustion chamber, makes my boiler adecided improvement on prior boilers of the kind in which a superheaterchamber at the front side of the boiler is merely equipped with asuperheater.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

1. In a water tube boiler, the combination of a combust'on chamber, asuperheater chamber provided with a superheater, means for establishingcommunication between said combustion chamber and the upper end of saidsuperheater chamber, and means within said superheater chamber, separateand distinct from said superheater, for cooling the gases and causingthem to flow downwardly through said chamber, thus inducing hot ases toenter said superheater chamber rom the combustion chamber and flowdownwardly through said chamber, at a high rate, over the superheatertherein.

2. A water tube boiler provided with a superheater chamber arranged insuch a manner that gases will enter the upper end of same from thecombustion chamber, circulate downward] through said chamber and thenreturn to t e combustion chamber, a superheater in said superheaterchamber, and water tubes in said superheater chamber that cool the gasesand cause a rapid down flow of hot gases through said superheaterchamber.

3. A water tube boiler provided with an upright superheater chamberarranged so that gases from the combustion chamber of the boiler-willenter the upper end of same, circulate downwardly through saidsuperheater chamber and then return to the combustion chamber,asuperheater in said superheater chamber, and water tubes in saidsuperheater chamber that form art of the heating surface of the boileran which cause the gases that enter said chamber to rapidly cool,contract and become of much greater density than the hot gases of thecombustion chamber.

4. A water tubeboiler provided with a combustion chamber, an upright suerheater chamber provided at its upper en with an inlet through whichgases enter from the combustion chamber and provided at its lower endwith an exit through which the gases return to the combustion chamber, asuperheater in .said superheater chamber, means in said superheaterchamber forming part of the heating surface of the boiler that causes arapid down draft of the gases over the superheater, and means forcontrolling the return of the cool gases to the combustion chamber.

5. A water tube boiler of the upright tube type having a front wall, asuperheater chamber interposed between said front wall and thecombustion chamber of the boiler, a superheater in said superheaterchamber. and water tubes in said superheater chamber that support thefront wall of the boiler.

6. A water tube boiler of the upright tuhc type provided with a frontwall. a baille or partition that co-operates with said front wall toform a superheater chamber. a superheater in said chamber, and watertubes in the superheater chamber and the combustion chamber that supportsaid front wall and said battle.

7. A water tube boiler having a main water circulatory path, asuperheater chamber arranged so that gases from the combustion chamberwill enter same. circulate downwardly therethrough and then return tothe combustion chamber. a superheater in said superheater chamber. andan auxiliary water circulatory path compnsing water tubes in thesuperheater chamber through which the water flows in one direction andalso water tubes in the combustion chamber through which the water flowsin the opposite direction.

8. In a water tube boiler of the upright tube type. the combination of acombustion chamber. a superheater chamber arranged outside .of the pathof the gases flowing through said combustion chamber and provided at itsupper and lower ends with openings that permit gases to pass from saidcombustion chamber into said superheater chamber. circulate downwardlythrough same and then return to the combustion chamber, a superheater insaid superheater chamber. and an auxiliary water rirculatorv paththrough which water flows in oppos te directions comp-rising water tubesin said superheater chamber that cool the gases and cause a down draftthrough said superheater thamber.

9. In a water tube boiler of the upright tube type. a combustionchamber, a superheater hamber. a bafile that separates said chambers andprovided at its upper and lower ends with gas inlets and outlets.respecwly, that establish communication between t tl chambers. acomplete auxiliary water circulatory path through which water flows inopposite directions comprising water wbcs in said tombustion chamberarranged 1 utsidc of the main path of the gases flowing through same andserving as a supporting means for said baille. a superheater in saidsuperheater chamber, and water tubes in said superheater chamber thatform part of said auxiliary circulatory path and which causc a downdraft through said superheater chamber by cooling the gases that entersaid superheater chamber.

[4 In a watertuhe boiler of the upright tube type, a combustion chamber,a superheater chamber. a battle that separates said chamhers andprovided at its upper and lower i chamber forming part of said auxil arywater circulatory path, that cause a down 'irat't through thesuperheater chamber by cooling the gases that enter said superheaterchamber, and means to control the fiow of gases from said superheaterchamber back to said combustion. chamber.

11. A water tube boiler of the upright tube type provided with anelevated drum forming part of the main water circulatory path of theboiler. an auxiliary water circulatory path comprising a lower waterdrum arranged at the front side of the boiler, a. bank of upfiow tubesleading from said lower drum to said elevated drum and arranged so thatthey will be exposed to the radiant heat of the gases in the combustionchamber and a bank of downflow tubes arranged in front of said bank ofuptlow tubes and having their opposite ends connected to said drums. ahafile supported on said haul; of upflow tubes. a wall supported on aidbank of downflow tubes and co-o erating with said baflle to form a supereat/er chamber, said baille having gas inlets at its upper and gasoutlets at its lower end which establish communication between saidsuperheater chamber and the combustion chamber of the boiler. and asuperheater in said superheater chamber.

12. A water tube boiler of the upright tube type provided with acombustion chamber that converges towards its upper end, a superheaterchamber arranged between said combustion chamber and the front wall ofthe boiler setting and having an inlet at its upper end through whichgases enter from the combustion chamber and an exit at its lower endthrough which the gases return to the combustion chamber, a superheaterin said superheater chamber, and downcomer water tubes in saidsuperheater chamber that form part of the water heating surface of theboiler and which cool the gases that enter the superheater chamber andthus cause a vigorous down draft of the gases through the superheaterchamber.

13. A water tube boiler, comprising a front steam-and-water drum thatforms part of the main water circulatory path of the boiler, a lowerdrum arranged at a point in advance of said steam-and-water drum andforming part of an auxiliary water circulatory path, a bank of downcomertubes and a bank of upconier tubes forming part of said auxiliarycirculatory path and connected at their upper and lower ends to saidsteam-and-water drum and to said lower water drum, respectively, a frontwall for the boiler setting supported by one of said banks of tubes, :1battle supported by said other bank of tubes and co-operating with saidfront wall to form a superheater chamber which communicates at its upperand lower ends with the combustion chamber at the rear side of saidbafile, and a superheater arranged in said superheater chamber.

14. A steam superheater, comprising a superheater chamber, means forestablishing communication between the upper end of said superheaterchamber and a combustion chamber, a superheater in said superheaterchamber, and means inside of said superheater chamber, separate anddistinct from the superheater therein, for cooling the gases and causingthem to flow down 'wardly through said chamber, thus inducing hot gasesto enter the upper end of said superheater chamber from the combustionchamber and circulate rapidly down through same over the superheater.

15. A steam superheater, comprising a. chamber arranged in such a waywith relation to a combustion chamber that gases will pass from thecombustion chamber into the upper end of said superheater chamber,circulate downwardly through same and then return to the combustionchamber, a superheater in said superheater chamber, and downcomcr watertubes in said superheater chamber that cool the gases and cause a rapiddownflow of hot gases through said superheater chamber,

16. A steam su erheater, comprising l chamber arranged in such a waywith relation to a combustion chamber that gases chamber that cool thegases and cause a will pass from the combustion chamber into rapiddownfiow of hot gases through said the u per end of said superheaterchamber superheater chamber, and means for control- 10 circu atedownwardly through same an ling the return of the cool gases to the com-5 then return to the combustion chamber, a, bustion chamber.

superheater in said superheater chamber, downcomer water tubes in saidsuperheater ALFRED COTTON.

